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midibob

Tales from Midibobs workshop JPM MPS2

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Test ROM works fine in the Emulator. The only things not emulated are the NMI interrupts for Reset SW and Watchdog timeout.

oh and DUART Loopback. All these will be fixed in the next release.

Edited by Wizard
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Ooh err missus! Put me out of my misery Chris, what am I missing? I can see the code running but can get it to do anything. I'm using somone else's layout to try it with but none of the switches do anything, same as on the board itself. You've obviously found the magic switch or link! If so how did you find it?

Maybe a magic word even?:lol:

 

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I did nothing special. Here is a screenshot of what my test layout looks like:

 

capture.JPG

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switch 11 is a full lamp test

switch 12 is a lamp column test

switch 13 is a lamp row test

switch 6, 7, 8 & 9 advance the reels, switch 5 does a reel reset and switch 6 does a similar thing but then steps them 3 steps extra

switch 25 steps through Triacs, Inhibits and Meters

switch 20-23 seem to do Duart testing

switch 29 tests the Alarm signal

switch 30 tests the watchdog timeout ( non functional atm )

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Wow, thanks for that Chris you are a star sir. I'm sure I tried 6,8 & 9 to no avail but most the others are down as 'not used' on my manual so will give them a go later.

Cheers
Bob

You sure you didn't have to say abracadabra too?

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Whoopee, lamp tests working. Now I can build a proper test rig.

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A giant leap for mankind more like!

Andrew are you thinking of making a full test rig? In that case I suppose it would make sense to build 2 the same rather than me riding off into the sunset and making something completely different. If you are it might be better if we start another thread in case anyone else wants to build one too.

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When I get to make something I will hopefully be using the led matrix I have already made as that’s the overall idea to make it universal with all. It so far works with barcrest and bell fruit boards so just a different set of connecting leads and it should work with these boards!!!

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I may have to resort back to using salvaged lamps which makes the box somewhat bigger, but it won't cost anything.

Anyway, time to roll the sleeves up and get stuck in.
The first board showed no 12v on the power  LED's and was due to one of those pesky tants being short. Once replaced on the next power up it came out of reset but only went as far as the top left hand 7 seg display. A quick check of the address lines showed there was nothing coming out of IC12 (74LS541) pin 18 BA15/CROUT. On checking the i/p on pin 2 there was nothing there either. Next step is the CPU and I was dreading that might be the problem, however checking pin 40 there was a good signal but nothing on the chip socket! Holding my test probe against the pin and the socket, to make the contact, and bingo she booted. A clean of the CPU pins and the socket appeared to do the trick but unfortunately it wouldn't pass the 'bash' test and just a light tap on the CPU was enough for it to crash! Next thing was to fit a new socket...

Some previous work had been done here and it didn't look too good underneath the socket...

646620163_P1040204(Custom).jpeg.3bf769df24dd58aecbf6fbca4ce5acfc.jpeg

With the socket removed it looked even worse..

791660010_P1040206(Custom).jpeg.2b8a49d4ac5c883ad84c6a4e1a3b0c5f.jpeg

After checking these broken tracks it appeared they all went to the 64 extension socket on the side. I don't know what this is used for but I'm sure somebody will enlighten me. It's obviously not neccessary for normal games as quite a few of the cases I've seen have a plastic blocking plate over it.

The dig holes will need to filled with epoxy and the tracks patched out if the owner wants the side port working, then a bit of solder resist to complete the job.

 

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Nice work Bob and a great start to wonderful world of mps !😁

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This is the finished board, it will go between the main MPS board and the reels, with the virus problems in China it looks like PCB production is going to be delayed

 

 

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Wow at that price it's not worth making your own.

I've been messing with the test software today and have found another couple of switches.

14 - Lamp count sequence 0-127
19 - 2 second alarm then lamp 0
28 - 4 second farting noise? :lol: (not sure what that signifies)

There must be a switch test in there somewhere but I haven't found it yet?

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6 hours ago, Andrew96_ said:

In production!!! £1.15 each!! Lol

7593CE2B-73CD-4283-AA84-AD4DB75B0AF2.thumb.jpeg.82eca5fbd2f10a1b9b12cf9ef7b09bd9.jpeg

Wow that’s bloody good! Crazy how they can do that! You will be knocking up M1 boards soon 😂😂😂

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3 hours ago, midibob said:

Wow at that price it's not worth making your own.

I've been messing with the test software today and have found another couple of switches.

14 - Lamp count sequence 0-127
19 - 2 second alarm then lamp 0
28 - 4 second farting noise? :lol: (not sure what that signifies)

There must be a switch test in there somewhere but I haven't found it yet?

Lamp 0 seems comes on for 1sec after initial power up, suggesting that 19 is doing a reset.

In the emu it just initiates a loop with interrupts on, so locks up, not sure how that resets a real board.

If you press the bushbutton on the board ( RAM reset ), lamp 0 and Lamp 1 light up after it restarts

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OK, that's good to know. Once I get the whole bank of switches set up hopefully I'll find where the switch test is?🤞

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That is so good progress is being made!!

 

pcb progress too! its now in 'copper deposition' process!!!

1890384762_pcbprocess.jpg.f620dedc03f23c468b2554a1c8e8c934.jpg

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The ones I make in my garage just have  'Is it done' Yes/No     :lol:

I've been looking at a design for the test rig and just realised the lamps on the official switch box cover 50-5F and 60-6F which are the hex outputs for the lamps multiplex. In that case I'm wondering if there's any point making a lamp multiplex box? Obviously it won't have the full load but it should show any problems I would have thought.

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don't forget there is also things like meter outputs, coin inhibits, reel drives, so I would think the lamps are not the only bits connected to the lamps!!

copper deposition is the plating through of copper in the drilled holes! I find it interesting the processes just making one circuit board goes through

Edited by Andrew96_

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14 hours ago, midibob said:

The ones I make in my garage just have  'Is it done' Yes/No     :lol:

I've been looking at a design for the test rig and just realised the lamps on the official switch box cover 50-5F and 60-6F which are the hex outputs for the lamps multiplex. In that case I'm wondering if there's any point making a lamp multiplex box? Obviously it won't have the full load but it should show any problems I would have thought.

You only need a full multiplex if your wanting to see the full range of lamps running game software, otherwise for testing your only really interested if each of the transistors work in the high and low side outputs so its just lamps needed for those devices, it does cut down the lamps from 256 to 32! I presume instead of 34v for multiplexed lights the test software just switches the output on and uses 12v for the lamps instead, that would make sense why there is a 'multiplex light' or 'test bed' switch!

 

824890786_pcbprogress.jpg.cc8eb4412fd483e5cc710e3980a5354e.jpg

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I don't know what you have Midibob, but I find I don't have enough program cards for the different roms I want to use on boards to test them. When I look on ebay they seem to go for quite a bit! so while they have special offer on PCB making I have decided to get some made,  I have reduced the width from 112mm to 100mm to get the special offer and they should still fit in the plastic housing if needed, but for test purposes these will do me!! I still have to check all the tracks again thoroughly in case I have missed something! but for now they seem good .

1523294360_MPSPROGCARD.thumb.jpg.ed9cb97028681382730e7a976b5d2d24.jpg

 

Edited by Andrew96_
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